1. Industrial Field of the Invention
The present invention relates to a thickness adjustable mold for continuous casting. More specifically, it relates to an improvement of a thickness adjustable mold in which the mold cavity is selectively defined to have a desired thickness by replacing only narrow face units held between a pair of wide face units.
2. Description of the Prior Art
In a conventional thickness adjustable mold, one of the wide face units constituting the mold is fixed, and the other wide face unit opposite to the fixed one is movably disposed. Narrow face units of a size corresponding to a desired thickness of a cast piece (hereinafter referred to as integral-type narrow face units) are replaceably held between those two wide face units.
With this structure, the whole narrow face units must be detached from the wide face units and replaced by new narrow face units for a desired cavity thickness. Also, various kinds of narrow face units for replacement which have sizes corresponding to predetermined thicknesses of cast pieces must be prepared in advance. Consequently, there are induced a problem that it takes a long time to change the mold size and a problem that expenses for such an equipment are high.
The inventors of the present invention have already proposed a thickness adjustable mold which enables on-line quick replacement of narrow face units (Japanese Patent Application No. 2-418217). As shown in FIG. 4, the basic structure of this adjustable mold comprises a fixed wide face unit 1, a movable wide face unit 2, and a pair of narrow face units 3 and 4 held between these two wide face units 1 and 2. A spindle 5 of a narrow face unit carriage device is connected to each of the narrow face units 3, 4. As shown in FIGS. 5 and 6, the narrow face units 3, 4 are each divided into a base narrow face unit member 11 and a replaceable narrow face unit member 12 (hereinafter referred to as separate-type narrow face units). The above-mentioned spindle 5 is connected to the base narrow face unit member 11, and a wide face copper plate 13 is secured on the replaceable narrow face unit member 12. When the thickness of a cast piece is changed, only the replaceable narrow face unit member 12 is detached by unfastening a bolt 16 and disengaging a hook 15, and a new replaceable narrow face unit member 12 for a desired cavity thickness is attached. In this method, replaceable narrow face unit members 12 for different cavity thicknesses, i.e., having different widths, are merely exchanged, and the base narrow face unit members 11 to which the spindles 5, water supply pipes and so forth are connected need not be detached. Consequently, the cavity thickness changing operation can be carried out relatively easily.
By the way, in the cavity thickness adjustable mold described above, the position of connection of each spindle 5 is unchanged. As shown in FIG. 4, therefore, once the spindle 5 is connected in alignment with the center of a specific narrow face unit 3, the spindle 5 must be connected to a narrow face unit 3 having a different width at an eccentric position.
With the above-described structure, however, when a narrow face unit 3 other than that specific narrow face unit is transferred in the wide face-wise direction, the narrow face unit 3 is distorted owing to eccentricity of the connecting portion, which results in a problem that the distorted narrow face unit 3 damages wide face copper plates 6. In order to solve this problem, the spindle 5 must be always aligned with the center of the narrow face unit 3 irrespective of the width of the narrow face unit 3. However, the structure for this alignment is complicated, and adjustment for such alignment is extremely troublesome.